Multi-speed transmission

ABSTRACT

A transmission of the present invention has an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes. The torque transmitting devices are selectively engageable in combinations of at least three to establish at least ten forward speed ratios and at least one reverse speed ratio.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices, and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches or brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In an aspect of the present invention a transmission is provided havingan input member, an output member, a first, second, third and fourthplanetary gear sets each having sun gears, carrier members and ringgears. The input member is continuously interconnected with the carriermember of the first planetary gear set. The output member iscontinuously interconnected with the carrier member of the fourthplanetary gear set.

Additionally, a first interconnecting member continuously interconnectsthe sun gear member of the first planetary gear set with a stationarymember, a second interconnecting member continuously interconnects thesun gear member of the second planetary gear set with the sun gearmember of the third planetary gear set, a third interconnecting membercontinuously interconnects the ring gear member of the second planetarygear set with the carrier member of the third planetary gear set and afourth interconnecting member continuously interconnects the carriermember of the third planetary gear set with the ring gear member of thefourth planetary gear set.

Further, a first torque transmitting device is selectively engageable tointerconnect the carrier member of the first planetary gear set with thecarrier member of the second planetary gear set, a second torquetransmitting device is selectively engageable to interconnect the ringgear member of the first planetary gear set with the sun gear member ofthe fourth planetary gear set, a third torque transmitting device isselectively engageable to interconnect the sun gear member of the thirdplanetary gear set with the sun gear member of the fourth planetary gearset, a fourth torque transmitting device is selectively engageable tointerconnect the sun gear member of the third planetary gear set withthe carrier member of the fourth planetary gear set, a fifth torquetransmitting device is selectively engageable to interconnect thecarrier member of the second planetary gear set with the stationarymember and a sixth torque transmitting device is selectively engageableto interconnect the ring gear member of the third planetary gear setwith the stationary member. The torque transmitting devices areselectively engageable in combinations of at least three to establish atleast ten forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.

It is thus an object of the present invention to provide a transmissionhaving four planetary gear sets.

It is a further object of the present invention to provide atransmission having ten forward speeds and at least one reverse.

It is a still further object of the present invention to provide atransmission having four planetary gear sets, a plurality of couplingmembers and a plurality of torque transmitting devices.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that in the particular exampleprovided, the ten speed automatic transmission of the present inventionhas an arrangement of permanent mechanical connections between theelements of the four planetary gear sets. A third component or elementof a first planetary gear set is permanently coupled to a ground or astationary member. A first component or element of the second planetarygear set is permanently coupled to a first component or element of athird planetary gear set. A third component or element of the secondplanetary gear set is permanently coupled to a second component orelement of a third planetary gear set. Finally, a second component orelement of the third planetary gear set is permanently coupled to athird component or element of a fourth planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear set are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear, one for the planet gearcarrier, and one for the ring gear. The relative length between thenodes of each lever can be used to represent the ring-to-sun ratio ofeach respective gear set. These lever ratios, in turn, are used to varythe gear ratios of the transmission in order to achieve appropriateratios and ratio progression. Mechanical couplings or interconnectionsbetween the nodes of the various planetary gear sets are illustrated bythin, horizontal lines and torque transmitting devices such as clutchesand brakes are presented as interleaved fingers. If the device is abrake, one set of the fingers is grounded. Further explanation of theformat, purpose and use of lever diagrams can be found in SAE Paper810102, “The Lever Analogy: A New Tool in Transmission Analysis” byBenford and Leising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the second node 14B of the firstplanetary gear set 14. The third node 14C of the first planetary gearset 14 is coupled to a stationary member or the transmission housing 50.The first node 16A of the second planetary gear set 16 is coupled to thefirst node 18A of the third planetary gear set 18. The third node 16C ofthe second planetary gear set 16 is coupled to the second node 18B ofthe third planetary gear set 18. The second node 18B of the thirdplanetary gear set 18 is coupled to the third node 20C of the fourthplanetary gear set 20. The output member 22 is coupled to the secondnode 20B of the fourth planetary gear set 20.

A first clutch 26 selectively connects the input member 12 and thesecond node 14B of the first planetary gear set 14 with the second node16B of the second planetary gear set 16. A second clutch 28 selectivelyconnects the first node 14A of the first planetary gear set 14 with thefirst node 20A of the fourth planetary gear set 20. A third clutch 30selectively connects the first node 18A of the third planetary gear set18 with the first node 20A of the fourth planetary gear set 20. A fourthclutch 32 selectively connects the first node 18A of the third planetarygear set 18 with the second node 20B of the fourth planetary gear set20. A first brake 34 selectively connects the second node 16B of thesecond planetary gear set 16 with a stationary element or a transmissionhousing 50. A second brake 36 selectively connects the third node 18C ofthe third planetary gear set 18 with the stationary element or thetransmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches, brakes, and couplings are correspondinglypresented whereas the nodes of the planetary gear sets now appear ascomponents of planetary gear sets such as sun gears, ring gears, planetgears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14A and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). Theplanet gears 14D are each configured to intermesh with both the sun gearmember 14C and the ring gear member 14A. The sun gear member 14C isconnected to a first shaft or interconnecting member 42 that ispermanently connected to a stationary member 50 thus preventing sun gearmember 14C from rotating relative to member 50. The ring gear member 14Ais connected for common rotation with a second shaft or interconnectingmember 44. The planet carrier member 14B is connected for commonrotation with a third shaft or interconnecting member 46 and with inputmember 12.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The planet gears16D are each configured to intermesh with both the sun gear member 16Aand the ring gear member 16C. The sun gear member 16A is connected forcommon rotation with a fourth shaft or interconnecting member 48. Thering gear member 16C is connected for common rotation with a fifth shaftor interconnecting member 52. The planet carrier member 16B is connectedfor common rotation with a sixth shaft or interconnecting member 54.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The set ofplanet gears 18D are each configured to intermesh with both the sun gearmember 18A and the ring gear member 18C. The sun gear member 18A isconnected for common rotation with the fourth shaft or interconnectingmember 48 and with a seventh shaft or interconnecting member 56. Theplanet carrier member 18B is connected for common rotation with thefifth shaft or interconnecting member 52 and with an eighth shaft orinterconnecting member 58.

The planetary gear set 20 includes a sun gear member 20A, a ring gearmember 20C and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The set ofplanet gears 20D are each configured to intermesh with both the sun gearmember 20A and ring gear member 20C. The sun gear member 20A isconnected for common rotation with a ninth shaft or interconnectingmember 60. The ring gear member 20C is connected for common rotationwith the eighth shaft or interconnecting member 58. The planet carriermember 20B is connected for common rotation with a ten shaft orinterconnecting member 62 and with the output shaft or member 22.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or the clutches 26, 28, 30, 32 andthe brakes 34 and 36 allow for selective interconnection of the shaftsor interconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the third shaft or interconnecting member 46 with the sixthshaft or interconnecting member 54. The second clutch 28 is selectivelyengageable to connect the second shaft or interconnecting member 44 withthe ninth shaft or interconnecting member 60. The third clutch 30 isselectively engageable to connect the seventh shaft or interconnectingmember 56 with the ninth shaft or interconnecting member 60. The fourthclutch 32 is selectively engageable to connect the seventh shaft orinterconnecting member 56 with the tenth shaft or interconnecting member62. The first brake 34 is selectively engageable to connect the sixthshaft or interconnecting member 54 with a stationary element or thetransmission housing 50 in order to prevent the sixth shaft orinterconnecting member 54 from rotating relative to the transmissionhousing 50. The second brake 36 is selectively engageable to connect thering gear member 18C with a stationary element or the transmissionhousing 50 in order to prevent the ring gear member 18C from rotatingrelative to the transmission housing 50.

Referring now to FIGS. 2 and 3, the operation of the embodiment of theten speed transmission 10 will be described. It will be appreciated thatthe transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with a double overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, fourth clutch 32, first brake 34 and second brake 36),as will be explained below. FIG. 3 is a truth table presenting thevarious combinations of torque-transmitting elements that are activatedor engaged to achieve the various gear states. Actual numerical gearratios of the various gear states are also presented although it shouldbe appreciated that these numerical values are exemplary only and thatthey may be adjusted over significant ranges to accommodate variousapplications and operational criteria of the transmission 10. An exampleof the gear ratios that may be obtained using the embodiments of thepresent invention are also shown in FIG. 3. Of course, other gear ratiosare achievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

To establish reverse gear, the second clutch 28, the third clutch 30 andthe first brake 34 are engaged or activated. The second clutch 28connects the second shaft or interconnecting member 44 with the ninthshaft or interconnecting member 60. The third clutch 30 connects theseventh shaft or interconnecting member 56 with the ninth shaft orinterconnecting member 60. The first brake 34 connects the sixth shaftor interconnecting member 54 with a stationary element or thetransmission housing 50 in order to prevent the sixth shaft orinterconnecting member 54 from rotating relative to the transmissionhousing 50. Likewise, the ten forward ratios are achieved throughdifferent combinations of clutch and brake engagement, as shown in FIG.3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches and brakes not specifically referenced in a given gearstate are inactive or disengaged and, second of all, that during gearshifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the third member of the first planetary gear set with astationary member; a second interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe first member of the third planetary gear set; a thirdinterconnecting member continuously interconnecting the third member ofthe second planetary gear set with the second member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe third member of the fourth planetary gear set; and six torquetransmitting devices each selectively engageable to interconnect atleast one of the first, second, and third members with at least oneother of the first members, second members, third members, and astationary member, and wherein the torque transmitting devices areselectively engageable in combinations of at least three to establish atleast ten forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.
 2. The transmission ofclaim 1 wherein a first of the six torque transmitting devices isselectively engageable to interconnect the second member of the firstplanetary gear set with the second member of the second planetary gearset.
 3. The transmission of claim 2 wherein a second of the six torquetransmitting devices is selectively engageable to interconnect the firstmember of the first planetary gear set with the first member of thefourth planetary gear set.
 4. The transmission of claim 3 wherein athird of the six torque transmitting devices is selectively engageableto interconnect the first member of the third planetary gear set withthe first member of the fourth planetary gear set.
 5. The transmissionof claim 4 wherein a fourth of the six torque transmitting devices isselectively engageable to interconnect the first member of the thirdplanetary gear set with the second member of the fourth planetary gearset.
 6. The transmission of claim 5 wherein a fifth of the six torquetransmitting devices is selectively engageable to interconnect thesecond member of the second planetary gear set with the stationarymember.
 7. The transmission of claim 6 wherein a sixth of the six torquetransmitting devices is selectively engageable to interconnect the thirdmember of the third planetary gear set with the stationary member. 8.The transmission of claim 1 wherein the third member of the firstplanetary gear set, the first member of the second planetary gear set,the first member of the third planetary gear set and the first member ofthe fourth planetary gear set are sun gears, the second member of thefirst planetary gear set, the second member of the second planetary gearset, the second member of the third planetary gear set and the secondmember of the fourth planetary gear set are carrier members and thefirst member of the first planetary gear set, the third member of thesecond planetary gear set, the third member of the third planetary gearset and the third member of the fourth planetary gear set are ringgears.
 9. The transmission of claim 1 wherein the input member iscontinuously interconnected with the second member of the firstplanetary gear set and wherein the output member is continuouslyinterconnected with the second member of the fourth planetary gear set.10. The transmission of claim 1 wherein two of the six torquetransmitting devices are brakes and four of the six torque transmittingdevices are clutches.
 11. The transmission of claim 1 wherein thestationary member is a transmission housing.
 12. A transmissioncomprising: an input member; an output member; first, second, third andfourth planetary gear sets each having first, second and third members,wherein the input member is continuously interconnected with the secondmember of the first planetary gear set and wherein the output member iscontinuously interconnected with the second member of the fourthplanetary gear set; a first interconnecting member continuouslyinterconnecting the third member of the first planetary gear set with astationary member; a second interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe first member of the third planetary gear set; a thirdinterconnecting member continuously interconnecting the third member ofthe second planetary gear set with the second member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe third member of the fourth planetary gear set; a first torquetransmitting device selectively engageable to interconnect the secondmember of the first planetary gear set with the second member of thesecond planetary gear set; a second torque transmitting deviceselectively engageable to interconnect the first member of the firstplanetary gear set with the first member of the fourth planetary gearset; a third torque transmitting device selectively engageable tointerconnect the first member of the third planetary gear set with thefirst member of the fourth planetary gear set; a fourth torquetransmitting device selectively engageable to interconnect the firstmember of the third planetary gear set with the second member of thefourth planetary gear set; and a fifth torque transmitting deviceselectively engageable to interconnect the second member of the secondplanetary gear set with the stationary member; and a sixth torquetransmitting device selectively engageable to interconnect the thirdmember of the third planetary gear set with the stationary member, andwherein the torque transmitting devices are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 13. The transmission of claim 12 wherein the thirdmember of the first planetary gear set, the first member of the secondplanetary gear set, the first member of the third planetary gear set andthe first member of the fourth planetary gear set are sun gears, thesecond member of the first planetary gear set, the second member of thesecond planetary gear set, the second member of the third planetary gearset and the second member of the fourth planetary gear set are carriermembers and the first member of the first planetary gear set, the thirdmember of the second planetary gear set, the third member of the thirdplanetary gear set and the third member of the fourth planetary gear setare ring gears.
 14. The transmission of claim 12 wherein the stationarymember is a transmission housing.
 15. A transmission comprising: aninput member; an output member; first, second, third and fourthplanetary gear sets each having sun gears, carrier members and ringgears, wherein the input member is continuously interconnected thecarrier member of the first planetary gear set and wherein the outputmember is continuously interconnected with the carrier member of thefourth planetary gear set; a first interconnecting member continuouslyinterconnecting the sun gear member of the first planetary gear set witha stationary member; a second interconnecting member continuouslyinterconnecting the sun gear member of the second planetary gear setwith the sun gear member of the third planetary gear set; a thirdinterconnecting member continuously interconnecting the ring gear memberof the second planetary gear set with the carrier member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the carrier member of the third planetary gear set withthe ring gear member of the fourth planetary gear set; a first torquetransmitting device selectively engageable to interconnect the carriermember of the first planetary gear set with the carrier member of thesecond planetary gear set; a second torque transmitting deviceselectively engageable to interconnect the ring gear member of the firstplanetary gear set with the sun gear member of the fourth planetary gearset; a third torque transmitting device selectively engageable tointerconnect the sun gear member of the third planetary gear set withthe sun gear member of the fourth planetary gear set; a fourth torquetransmitting device selectively engageable to interconnect the sun gearmember of the third planetary gear set with the carrier member of thefourth planetary gear set; and a fifth torque transmitting deviceselectively engageable to interconnect the carrier member of the secondplanetary gear set with the stationary member; and a sixth torquetransmitting device selectively engageable to interconnect the ring gearmember of the third planetary gear set with the stationary member, andwherein the torque transmitting devices are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 16. The transmission of claim 15 wherein thestationary member is a transmission housing.